Method and Apparatus for Updating Data Usage in Wireless Communication System

This application is a U.S. National Stage application under 35 U.S.C. § 371 of an International application number PCT/KR2023/010970, filed on Jul. 27, 2023, which is based on and claims priority of a Korean patent application number 10-2022-0094100, filed on Jul. 28, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

The disclosure relates to a wireless communication system, and more particularly, to a method and device for updating data usage.

5G mobile communication technology defines a wide frequency band to enable a fast transmission speed and new services, and may be implemented not only in a frequency (‘sub 6 GHz’) band of 6 GHz or less such as 3.5 GHz, but also in an ultra high frequency band (‘above 6 GHz’) called a mmWave such as 28 GHz and 39 GHz. Further, in the case of 6G mobile communication technology, which is referred to as a beyond 5G system, in order to achieve a transmission speed that is 50 times faster than that of 5G mobile communication technology and ultra-low latency reduced to 1/10 compared to that of 5G mobile communication technology, implementations in terahertz bands (e.g., such as 95 GHz to 3 terahertz (3 THz) band) are being considered.

In the early days of 5G mobile communication technology, with the goal of satisfying the service support and performance requirements for an enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), standardization has been carried out for beamforming and massive multi-input multi-output (MIMO) for mitigating a path loss of radio waves in an ultra-high frequency band and increasing a propagation distance of radio waves, support for various numerologies (multiple subcarrier spacing operation, and the like) for efficient use of ultra-high frequency resources and dynamic operation for slot formats, initial access technology for supporting multi-beam transmission and broadband, a definition and operation of a band-width part (BWP), a new channel coding method such as low density parity check (LDPC) code for large capacity data transmission and polar code for high reliable transmission of control information, L2 pre-processing, and network slicing that provides a dedicated network specialized for specific services.

Currently, discussions are ongoing to improve initial 5G mobile communication technology and enhance a performance thereof in consideration of services in which 5G mobile communication technology was intended to support, and physical layer standardization for technologies such as vehicle-to-everything (V2X) for helping driving determination of an autonomous vehicle and increasing user convenience based on a location and status information of the vehicle transmitted by the vehicle, new radio unlicensed (NR-U) for the purpose of a system operation that meets various regulatory requirements in unlicensed bands, NR UE power saving, a non-terrestrial network (NTN), which is direct UE-satellite communication for securing coverage in regions where communication with a terrestrial network is impossible, and positioning is in progress.

Further, standardization in the field of air interface architecture/protocol for technologies such as industrial Internet of things (IIoT) for supporting new services through linkage and convergence with other industries, integrated access and backhaul (IAB) that provides nodes for expanding network service regions by integrating wireless backhaul links and access links, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and 2-step RACH for NR that simplifies a random access procedure is also in progress, and standardization in the field of system architecture/service for 5G baseline architecture (e.g., service based architecture, service based interface) for applying network functions virtualization (NFV) and software-defined networking (SDN) technologies, mobile edge computing (MEC) that receives services based on a location of a UE, and the like is also in progress.

When such a 5G mobile communication system is commercialized, connected devices in an explosive increase trend will be connected to communication networks; thus, it is expected that function and performance enhancement of a 5G mobile communication system and integrated operation of connected devices will be required. To this end, new research on extended reality (XR) for efficiently supporting augmented reality (AR), virtual reality (VR), mixed reality (MR), and the like, 5G performance improvement and complexity reduction using artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication will be conducted.

Further, the development of such a 5G mobile communication system will be the basis for the development of full duplex technology for improving frequency efficiency and system network of 6G mobile communication technology, satellite, artificial intelligence (AI)-based communication technology that utilizes AI from a design stage and that realizes system optimization by internalizing end-to-end AI support functions, and next generation distributed computing technology that realizes complex services beyond the limits of UE computing capabilities by utilizing ultra-high performance communication and computing resources as well as a new waveform for ensuring coverage in a terahertz band of 6G mobile communication technology, full dimensional MIMO (FD-MIMO), multi-antenna transmission technologies such as an array antenna and large scale antenna, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) technology.

The disclosure provides a method and device for updating data usage for efficiently deriving a remaining allowed usage value even in a situation where there are multiple PDU sessions corresponding to S-NSSAI and DNN and where there are multiple SMFs and PCFs in charge of the corresponding PDU sessions in a wireless communication system.

According to the disclosure, a method of operating a first session management function (SMF) in a wireless communication system includes receiving, from an access and mobility management function (AMF), an SM context creation request message; transmitting, to a first policy control function (PCF), a policy creation request message based on the SM context creation request message; and receiving, from the first PCF, a first response message to the policy creation request message.

According to the disclosure, a first SMF in a wireless communication system includes a transceiver; and a processor coupled with the transceiver. The processor receives, from an AMF, an SM context creation request message, transmits, to a first PCF, a policy creation request message based on the SM context creation request message, and receives, from the first PCF, a first response message to the policy creation request message.

The SM context creation request message may be generated based on a first response message transmitted from a second SMF to the AMF.

The first response message may include information indicating whether an update on data usage of the terminal has been completed in the second SMF.

The first response message may be generated based on a second response message transmitted from a second PCF to the second SMF.

The second response message may include information indicating whether an update on data usage of the terminal has been completed in the second PCF.

The second response message may be generated based on a third response message transmitted from a unified data repository (UDR) to the second PCF.

The third response message may include information indicating whether an update on data usage of the terminal has been completed in the UDR.

The third response message may be generated based on an update request message transmitted from the second PCF to the UDR.

The update request message may include information instructing to update data usage of the terminal.

The update request message may be generated based on a policy update request message transmitted from the second SMF to the second PCF.

The policy update request message may include information instructing to update data usage of the terminal.

The policy update request message may be generated based on an SM context update request message transmitted from the AMF to the second SMF.

The SM context update request message may include at least one of S-NSSAI, DNN, report indication, per S-NSSAI/DNN report indication, PDU session ID, or SM context ID.

The SM context request message may be generated based on a PDU session establishment request message transmitted from the terminal to the AMF.

The PDU session establishment request message may include at least one of S-NSSAI, DNN, or PDU session ID.

The first response message may be generated based on a fourth response message transmitted from a UDR to the first PCF.

The fourth response message may include at least one of remaining allowed usage corresponding to an UE ID, DNN, or S-NSSAI.

The fourth response message may be generated based on a query request message transmitted from the first PCF to the UDR.

The query request message may be generated based on the policy creation request message.

A method and device for updating data usage in a wireless communication system according to the disclosure have the effect of efficiently deriving a remaining allowed usage value even in a situation where there are multiple PDU sessions corresponding to S-NSSAI and DNN and where there are multiple SMFs and PCFs in charge of the corresponding PDU sessions.

Hereinafter, preferred embodiments of the disclosure will be described in detail with reference to the attached drawings. In this case, it should be noted that in the attached drawings, identical components are indicated by identical symbols whenever possible. Further, detailed descriptions of well-known functions and constitutions that may obscure the gist of the disclosure will be omitted.

In describing embodiments in this specification, descriptions of technical contents that are well known in the technical field to which the disclosure pertains and that are not directly related to the disclosure will be omitted. This is to more clearly convey the gist of the disclosure without obscuring the gist of the disclosure by omitting unnecessary description.

For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. Further, the size of each component does not fully reflect the actual size. In each drawing, the same reference numerals are given to the same or corresponding components.

Advantages and features of the disclosure, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only embodiments of the disclosure enable the disclosure to be complete, and are provided to fully inform the scope of the disclosure to those of ordinary skill in the art to which the disclosure belongs, and the disclosure is only defined by the scope of the claims. Like reference numerals refer to like components throughout the specification.

In this case, it will be understood that each block of message flow diagrams and combinations of the message flow diagrams may be performed by computer program instructions. Because these computer program instructions may be mounted in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, the instructions performed by a processor of a computer or other programmable data processing equipment generate a means that performs functions described in the message flow diagram block(s). Because these computer program instructions may be stored in a computer usable or computer readable memory that may direct a computer or other programmable data processing equipment in order to implement a function in a particular manner, the instructions stored in the computer usable or computer readable memory may produce a production article containing instruction means for performing the function described in the message flow diagram block(s). Because the computer program instructions may be mounted on a computer or other programmable data processing equipment, a series of operation steps are performed on the computer or other programmable data processing equipment to generate a computer-executable process; thus, instructions for performing the computer or other programmable data processing equipment may provide steps for performing functions described in the message flow diagram block(s).

Further, each block may represent a portion of a module, a segment, or a code including one or more executable instructions for executing a specified logical function(s). Further, it should be noted that in some alternative implementations, functions recited in the blocks may occur out of order. For example, two blocks illustrated one after another may in fact be performed substantially simultaneously, or the blocks may be sometimes performed in the reverse order according to the corresponding function.

In this case, the term ‘-unit’ used in this embodiment means software or hardware components such as field programmable gate array (FPGA) or application specific integrated circuit (ASIC), and ‘-unit’ performs certain roles. However, ‘-unit’ is not limited to software or hardware. ‘-unit’ may be constituted to reside in an addressable storage medium or may be constituted to reproduce one or more processors. Therefore, as an example, ‘-unit’ includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuit, data, databases, data structures, tables, arrays, and variables. Functions provided in the components and ‘-units’ may be combined into a smaller number of components and ‘-units’ or may be further separated into additional components and ‘-units’. Further, components and ‘-units’ may be implemented to reproduce one or more CPUs in a device or secure multimedia card.

Hereinafter, the base station is a subject performing resource allocation of the terminal and may be at least one of a node B, a base station (BS), an eNode B (eNode B), a gNode B (gNB), a radio access unit, a base station controller, or a node on the network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Further, the embodiment of the disclosure may be applied to other communication systems having a similar technical background or channel type to the embodiment of the disclosure described below. Further, the embodiments of the disclosure may be applied to other communication systems through some modifications within a range that does not significantly depart from the scope of the disclosure by determination of a person having skilled technical knowledge.

A term for identifying an access node used in the following description, a term referring to a network entity or a network function (NF), a term referring to messages, a term referring to an interface between network objects, and terms referring to various identification information are exemplified for convenience of description. Accordingly, the disclosure is not limited to the terms described below, and other terms referring to an object having an equivalent technical meaning may be used.

Hereinafter, for convenience of description, some terms and names defined in the 3rd generation partnership project long term evolution (3GPP) standard may be used. However, the disclosure is not limited by the above terms and names, and may be equally applied to systems conforming to other standards.

1 FIG. 10 is a conceptual diagram illustrating a wireless communication systemaccording to the disclosure.

1 FIG. 10 With reference to, network entities or network nodes constituting the wireless communication systemare described as follows.

200 100 100 A (radio) access network ((R) AN)is a subject performing radio resource allocation of a terminal, and may be at least one of an eNode B, a node B, a base station (BS), a NextGeneration radio access network (NG-RAN), a 5G-AN, a wireless access unit, a base station controller, or a node on a network. The terminalmay include a user equipment (UE), a NextGeneration UE (NG UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. Further, although embodiments of the disclosure are described below using a 5G system as an example, the embodiments of the disclosure may be applied to other communication systems having a similar technical background. Further, the embodiments of the disclosure may be applied to other communication systems through some modifications within a range that does not significantly deviate from the scope of the disclosure by the determination of a person having skilled technical knowledge.

While a wireless communication system evolves from a 4G system to a 5G system, a NextGen core (NG Core) or 5G core network (5GC), which is a new core network, is defined. The new core network virtualizes all existing network entities (NEs) to create network functions (NFs). According to an embodiment of the disclosure, an NF may mean a network entity, a network component, or a network resource.

300 400 500 600 700 800 900 1000 1500 1600 1700 1800 1 FIG. 1 FIG. 1 FIG. According to the disclosure, 5GC may include NFs,,,,,,,,,,, andillustrated in. The disclosure is not limited to the example illustrated in, and the 5GC may include a greater number of NFs or a fewer number of NFs than those illustrated in.

500 100 According to the disclosure, an access and mobility management function (AMF)may be an NF of managing the mobility of the UE.

600 100 According to the disclosure, a session management function (SMF)may be an NF of managing a packet data network (PDN) connection provided to the UE. The PDN connection may be referred to as a packet data unit (PDU) session.

700 100 According to the disclosure, a policy control function (PCF)may be an NF of applying a mobile communication service provider's service policy and charging policy to the UE, and policy for a PDU session.

1000 According to the disclosure, a unified data management (UDM)may be an NF of storing information on subscribers.

1500 100 1500 According to the disclosure, a network exposure function (NEF)may be a function of providing information on the UEto a server outside the 5G network. Further, the NEFmay provide a function of providing information necessary for a service to the 5G network and storing the information in a UDR (not illustrated).

300 400 According to the disclosure, a user plane function (UPF)may be a function of performing the role of a gateway that transmits user data (PDU) to a data network (DN).

1600 According to the disclosure, a network repository function (NRF)may perform a function of discovering an NF.

900 According to the disclosure, an authentication server function (AUSF)may perform UE authentication in a 3GPP access network and a non-3GPP access network.

800 100 According to the disclosure, a network slice selection function (NSSF)may perform a function of selecting a network slice instance provided to the UE.

400 100 According to the disclosure, the data network (DN)may be a data network in which the UEtransmits and receives data in order to use a network operator's service or a third party service.

700 600 700 700 In a 5G system, a PDU session capable of transmitting and receiving traffic may be created for a specific DNN (i.e., data network name) and S-NSSAI (i.e., network slice identifier). In a 5G system, the PCFperiodically receives a report of data usage for S-NSSAI and DNN for each UE from the SMF, and updates remaining allowed usage for S-NSSAI and DNN for each UE based on the report. Further, the PCFthat determines a policy for a session determines the policy for the session with reference to the remaining allowed usage for the corresponding S-NSSAI and DNN in a PDU session creation procedure. For example, in the case that the remaining allowed usage is almost zero, the PCFmay not create a QoS flow for the corresponding PDU session or may select a very low quality QoS parameter so that the remaining allowed usage does not fall below 0.

700 In a situation where there are multiple PDU sessions for S-NSSAI and DNN, a update on remaining allowed usage is performed independently for each PDU session, and in the case that a new PDU session creation procedure is performed for the corresponding S-NSSAI and DNN, a method of enabling the remaining allowed usage referenced by the PCFto be maintained to the latest value is required. That is, a method of enabling data usage for other existing PDU sessions to be always reflected is required.

10 The disclosure provides technology for efficiently updating remaining allowed usage to the latest value in the wireless communication system.

700 In a situation where there are multiple PDU sessions for S-NSSAI and DNN (e.g., in the case of an SSC mode 3 PDU session, when a change in the user plane function (UPF) in charge of the PDU session is required, a new PDU session that may replace the corresponding PDU session may be created first and the existing PDU session may be released), in the case that a update on remaining allowed usage is independently performed for each PDU session and that a new PDU session creation procedure is performed for the corresponding S-NSSAI and DNN, a method of enabling the remaining allowed usage referenced by the PCFto be maintained to the latest value is required. That is, a method of enabling data usage for other existing PDU sessions to be always reflected is required.

600 700 500 700 1100 700 The disclosure proposes a method of requesting a data usage update to SMFs/PCFsin charge of the same S-NSSAI/DNN when the AMFreceives a session creation request for S-NSSAI/DNN, a method of requesting a data usage update to PCFsin charge of the same S-NSSAI/DNN when a unified data repository (UDR)receives a query request for S-NSSAI/DNN, and a method of selecting the same PCFfor S-NSSAI and DNN.

2 FIG. 610 620 710 720 500 10 is a message flow diagram illustrating an operation of requesting a data usage update to SMFsand/PCFsandin charge of the same S-NSSAI/DNN when an AMFreceives a session creation request for S-NSSAI/DNN in a wireless communication systemaccording to the disclosure.

0 At step, there may be one or more PDU sessions already established with a specific DNN and S-NSSAI. For example, a PDU session for the same DNN/S-NSSAI as that of an SSC mode 3 PDU session may be established.

1 100 500 200 500 100 200 At step, the UEmay transmit a PDU session establishment request message to the AMFthrough the RAN. The AMFmay receive the PDU session establishment request message from the UEthrough the RAN. The PDU session establishment request message may include S-NSSAI, DNN, and PDU session ID.

For example, in the case of an SSC mode 3 procedure (i.e., a procedure for creating a new PDU session to replace an old PDU session because a change in anchor UPF is required for the old PDU session), the PDU session establishment request message may include an old PDU session ID. The old PDU session ID may indicate identifier information on the existing PDU session established with the same S-NSSAI and DNN as those included in the PDU session establishment request message.

2 500 610 610 500 At step, the AMFmay transmit an SM context update request message (Nsmf_PDUSession_UpdateSMContext request (report indication)) to an SMF_E. The SMF_Emay receive the SM context update request message from the AMF.

1 1 1 500 710 610 610 610 620 610 500 610 For example, if there are already established PDU sessions having the same S-NSSAI and DNN as those included in the PDU session establishment request message received at step, or if the PDU session establishment request message received at stepincludes an old PDU session ID and has received an SMF relocation indication (i.e., information indicating that an SMF change is required) before step, the AMFmay determine to transmit an SM context update request message (Nsmf_PDUSession_UpdateSMContext request (report indication)) instructing to update data usage up to now to a PCF_Eto the SMFs(i.e., SMF_E, indicating the SMF in charge of the existing PDU session) in charge of the corresponding PDU sessions (i.e., PDU sessions having the same S-NSSAI and DNN and managed by SMFsdifferent from an SMFto be in charge of a new PDU session). In this case, in the case that there are multiple SMF_Esin charge of PDU sessions, the AMFmay transmit a PDU session update request message to each SMF_E. The SM context update request message may include at least one of the following information:

1 S-NSSAI, DNN: The same S-NSSAI and DNN as those included in the PDU session request message received at stepmay be included.

610 710 500 1 Report indication: Information instructing to transmit a message reporting data usage up to now to the SMF_Eto the PCF_E. Further, in the case that there is (are) an SM policy association ID(s) for PDU sessions requiring update, which is information received by the AMFbefore stepin the report indication, the report indication may include corresponding information.

500 610 710 610 500 If a message from the AMFincludes a report indication, the SMF_Emay transmit a message reporting data usage up to now for a target of the usage update request to the PCF_E. The SMF_Emay identify information on the target of the usage update request through the S-NSSAI and DNN or SM policy association ID included in the SM context update request message received from the AMF, or through the SM policy association ID included in the report indication.

610 500 610 500 Per S-NSSAI/DNN report indication: It is optional information transmitted together with the report indication, and in the case that the same SMF_Ehas multiple PDU sessions for the S-NSSAI and DNN, in order to reduce a signaling load, the AMFmay transmit only one request including per S-NSSAI/DNN report indication to the corresponding SMF_E. For example, the AMFmay not transmit a message for each session.

1 PDU Session ID: It may be an identifier for a PDU session having the same S-NSSAI and DNN as those included in the PDU session establishment request message received at step.

1 SM context ID: It may be an identifier that identifies a connection established in advance between the corresponding AMF and SMF in order to transmit and receive information on a PDU session having the same S-NSSAI and DNN as those included in the PDU session establishment request message received at step.

3 610 710 710 610 At step, the SMF_Emay transmit a policy update request message (Npcf_SM PolicyUpdate Request) to the PCF_E. The PCF_Emay receive the policy update request message from the SMF_E.

2 610 2 710 610 300 For example, in the case that the PDU session update request message received at stepincludes a report indication, the SMF_Emay include aggregated data usage (i.e., data usage up to now after the last update to the PCF) for the PDU session established for S-NSSAI and DNN included in the PDU session update request message received at stepin the policy update request message transmitting to the PCF_E. For this purpose, the SMF_Emay request an update to the UPF.

610 710 2 710 The SMF_Emay identify the PCF_Ein charge of the corresponding PDU session and SM policy association ID (an identifier that identifies a connection for the SMF to exchange information on the corresponding PDU session with the corresponding PCF) based on information included in the PDU session update request message received at step(e.g., PDU session ID, SM context ID, or S-NSSAI and DNN), and transmit a policy update request message to the corresponding PCF_E.

2 610 In the case that there is a per S-NSSAI/DNN report indication in the PDU session update request message received at step, the SMF_Emay identify SM policy association IDs for PDU sessions to be monitored among all PDU sessions for S-NSSAI and DNN in which it is in charge of, and transmit a message for each SM policy association ID to PCF(s) in charge of the corresponding SM policy association IDs.

710 For example, a policy update request message transmitted to the PCF_Emay include at least one of aggregated data usage, S-NSSAI, DNN, UE ID, or SM policy association ID.

4 710 1100 1100 710 At step, the PCF_Emay transmit an update request message (Nudr_DM_Update request) to the UDR. The UDRmay receive the update request message from the PCF_E.

610 3 710 610 3 610 3 710 3 710 1100 710 1100 5 710 1100 For example, if the policy update message received from the SMF_Eat stepincludes aggregated data usage, the PCF_Emay identify a UE identifier (i.e., UE ID) based on information included in the policy update message received from the SMF_Eat step. The SMF_Emay update remaining allowed usage corresponding to the S-NSSAI and DNN received at stepfor the corresponding UE corresponding to the identified UE identifier. The PCF_Emay calculate a value obtained by subtracting the aggregated data usage value received at stepfrom the existing remaining allowed usage values for the UE ID, S-NSSAI, and DNN as a new remaining allowed usage value for the UE ID, S-NSSAI, and DNN and store the value. Further, the PCF_Emay include aggregated data usage in an update request message transmitting to the UDRinstead of directly updating the remaining allowed usage value and including a new remaining allowed usage value. In this case, the PCF_Emay store the remaining allowed usage value included in the response message received from the UDRat stepas a new remaining allowed usage value. The PCF_Emay transmit an update request message for updating the remaining allowed usage value to the UDRstoring remaining allowed usage for the UE ID, S-NSSAI, and DNN. The update request message may include at least one of S-NSSAI, DNN, UE ID, new remaining allowed usage, or aggregated data usage.

5 1100 710 710 1100 At step, the UDRmay transmit a response message to the PCF_E. The PCF_Emay receive the response message from the UDR.

4 1100 4 For example, if the update request message received at stepincludes remaining allowed usage or aggregated data usage, or both, the UDRmay update the remaining allowed usage corresponding to the UE ID, S-NSSAI, and DNN received at step.

1100 4 The UDRmay store the remaining allowed usage received at stepas a new remaining allowed usage value.

4 4 1100 4 1100 710 4 In this case, in the case that the remaining allowed usage received at stepis different from a value obtained by subtracting the aggregated data usage value received at stepfrom the remaining allowed usage stored by the UDR, the value obtained by subtracting the aggregated data usage value received at stepfrom the remaining allowed usage stored by the UDRmay be stored as the remaining allowed usage. In this case, the response message transmitted to the PCF_Ein response to the update request message received at stepmay include new remaining allowed usage.

1100 The UDRmay include information indicating whether the update was successful in the response message and new remaining allowed usage.

6 710 610 610 710 710 610 3 5 At step, the PCF_Emay transmit a response message to the SMF_E. The SMF_Emay receive the response message from the PCF_E. For example, the PCF_Emay transmit a response message including information indicating whether the update was successful to the SMF_Ein response to the policy update request message received at stepbased on the information indicating whether the update was successful, received at step.

7 610 500 500 610 610 500 500 2 6 At step, the SMF_Emay transmit a response message to the AMF. The AMFmay receive the response message from the SMF_E. For example, the SMF_Emay transmit a response message including information indicating whether the update was successful to the AMFin response to the PDU session update request message received from the AMFat stepbased on the information indicating whether the update was successful, received at step.

8 500 620 620 500 a, At stepthe AMFmay transmit an SM context creation request message (Nsmf_PDUSession_CreateSMContext request) to the SMF_N. The SMF_Nmay receive the SM context creation request message from the AMF.

500 620 1 500 1 1 500 620 610 500 620 For example, the AMFmay select the SMF_N(indicating an SMF to be in charge of a new PDU session) to be in charge of a new PDU session corresponding to S-NSSAI and DNN included in PDU session establishment request message received at step. If the AMFhas received an old PDU session ID at stepand received SMF relocation indication (i.e., information indicating that an SMF change is required) before step, the AMFmay select a new SMF_Ndifferent from the SMF_Ein charge of a PDU session corresponding to the old PDU session ID. The AMFmay transmit an SM context creation request message to the selected SMF_N. For example, the SM context creation request message may include at least one of an UE ID, S-NSSAI, DNN, or PDU session ID.

8 620 500 500 620 620 1000 8 620 b, a. At stepthe SMF_Nmay transmit a response message to the AMF. The AMFmay receive the response message from the SMF_N. For example, the SMF_Nmay request and receive session related subscription information to and from the UDMbased on the UE ID received at stepThe SMF_Nmay create an SM context and SM context ID based on the received session related subscription information.

620 8 500 a The SMF_Nmay transmit a response message including the result (i.e., success or failure) of the request at stepand SM context ID to the AMF.

9 620 720 720 620 620 500 8 620 610 720 710 a At step, the SMF_Nmay transmit an SM policy creation request message to the PCF_N. The PCF_Nmay receive an SM policy creation request message from the SMF_N. The SMF_Nmay select a PCF for transmitting the SM policy request message. For example, in the case that the SM context creation request message received from the AMFat stepincludes a PCF ID or information indicating to select the same PCF for the same S-NSSAI and DNN (or in the case that the SM context creation request message is stored as preconfigured information), the SMF_Nmay select a PCF based on the corresponding information. For example, the same PCF as the PCF_Emay be selected (i.e., the PCF_Nand the PCF_Eare the same).

620 720 The SMF_Nmay transmit an SM policy creation request message for SM policy creation to the selected PCF (i.e., PCF_N).

2 FIG. 620 720 620 8 720 620 720 720 620 720 1100 1100 720 1100 1100 a Although not illustrated in, the SMF_Nmay perform the following procedure before transmitting an SM policy request message for SM policy creation to the PCF_N. When, among PDU sessions in which the SMF_Nis in charge of, PDU sessions corresponding to the same S-NSSAI and DNN as those included in the SM context creation request message received at stepalready exist, and in the case that the PCF(s) for the corresponding PDU sessions are different from the selected PCF_N, the SMF_Nmay transmit aggregated data usage (i.e., data usage up to now after the last update to the PCF) for the corresponding PDU sessions to the corresponding PCF_Nto update data usage. The PCF_Nmay receive a message including aggregated data usage from the SMF_N. The PCF_Nmay transmit an update request message (Nudr_DM_Update request) including at least one of aggregated data usage or newly calculated remaining allowed usage to the UDR. The UDRmay receive the update request message from the PCF_N. The UDRmay update remaining allowed usage corresponding to the UE ID, S-NSSAI, and DNN stored in the UDRbased on the update request message.

10 720 1110 1110 720 720 9 1110 At step, the PCF_Nmay transmit a query request message (Nudr_DM_Query request) to the UDR. The UDRmay receive the query request message from the PCF_N. For example, the PCF_Nmay transmit a query request message for requesting remaining allowed usage corresponding to the UE ID, DNN, and S-NSSAI received at stepto the UDR.

2 FIG. 720 1100 Although not illustrated in, the PCF_Nmay perform the following procedure before transmitting a query request message for requesting remaining allowed usage corresponding to the UE ID, DNN, and S-NSSAI to the UDR.

620 9 720 9 720 720 720 720 In the case that there are PDU sessions that do not receive an SM policy creation request message for data usage update from the SMF_Nat stepamong PDU sessions that the PCF_Nis in charge of, and among SM policies (or PDU sessions) corresponding to the same S-NSSAI and DNN as those included in the SM policy creation request message received from step, the PCF_Nmay transmit a message requesting to update data usage to SMFs in charge of the corresponding PDU sessions. For example, the message requesting to update data usage may include an SM policy association ID, S-NSSAI, DNN, and usage report information (information indicating to immediately report data usage). Each SMF may receive a message requesting to update data usage from the PCF_N. Each SMF may transmit a response message including aggregated data usage in response to the message requesting to update data usage to the PCF_N. The PCF_Nmay receive a response message including aggregated data usage from each SMF.

11 1110 720 720 1110 1100 10 720 At step, the UDRmay transmit a response message to the PCF_N. The PCF_Nmay receive the response message from the UDR. For example, the UDRmay transmit a response message including remaining allowed usage corresponding to the UE ID, DNN, and S-NSSAI included in the query request message received at stepto the PCF_N.

720 9 The PCF_Nmay determine a session related policy (e.g., QoS parameters) corresponding to the SM policy request received at stepbased on the received remaining allowed usage.

1110 2 7 9 10 720 1100 For example, the UDRmay maintain a latest remaining allowed usage value through the remaining allowed usage update procedure performed at stepsto, and the remaining allowed usage update procedure performed at stepsand. The PCF_Nmay determine a session related policy based on the latest remaining allowed usage value received from the UDR.

12 720 620 620 720 720 9 620 At step, the PCF_Nmay transmit a response message to the SMF_N. The SMF_Nmay receive the response message from the PCF_N. The PCF_Nmay transmit a response message including the result (i.e., success or failure) of the request, SM policy association ID, and session related policy information in response to the SM policy creation message received at stepto the SMF_N.

13 100 500 610 620 710 720 1100 100 500 610 620 710 720 1100 At step, a PDU session establishment procedure may be performed in the UE, the AMF, the SMF_E, the SMF, the PCF_E, the PCF_N, and the UDR. For example, a rest of the PDU session establishment procedure may be performed in the UE, the AMF, the SMF_E, the SMF, the PCF_E, the PCF_N, and the UDR.

3 FIG. 1100 10 is a message flow diagram illustrating an operation of requesting a data usage update to PCFs in charge of the same S-NSSAI/DNN when a UDRreceives a query request for S-NSSAI/DNN in a wireless communication systemaccording to the disclosure.

2 FIG. 0 100 500 610 620 710 720 1100 100 500 610 620 710 720 1100 With reference to, at step, among at least one of the UE, the AMF, the SMF_E, the SMF, the PCF_E, the PCF_N, or the UDR, there may be one or more PDU sessions already established with a specific DNN and S-NSSAI. For example, among at least one of the UE, the AMF, the SMF_E, the SMF, the PCF_E, the PCF_N, or the UDR, a PDU session for the DNN and S-NSSAI such as an SSC mode 3 PUD session may be established.

1 100 500 200 500 100 200 At step, the UEmay transmit a PDU session establishment request message to the AMFthrough the RAN. The AMFmay receive the PDU session establishment request message from the UEthrough the RAN. The PDU session establishment message may include S-NSSAI, DNN, and PDU session ID.

610 For example, in the case of an SSC mode 3 procedure (i.e., a procedure for creating a new PDU session to replace an old PDU session because a change in anchor UPF is required for the old PDU session managed by the SMF_E), the PDU session establishment message may include an old PDU session ID. The old PDU session ID may indicate identifier information on the existing PDU session established with the same S-NSSAI and DNN as those included in the PDU session establishment message.

2 500 620 620 500 500 610 1 500 1 1 500 620 610 620 2 500 620 a, a At stepthe AMFmay transmit an SM context creation request message (Nsmf_PDUSession_CreateSMContext request) to the SMF_N. The SMF_Nmay receive the SM context creation request message from the AMF. For example, the AMFmay select the SMF_N(indicating an SMF to be in charge of the new PDU session) to be in charge of a new PDU session corresponding to S-NSSAI and DNN included in the PDU session establishment request message received at step. If the AMFhas received an old PDU session ID at stepand received an SMF relocation indication (i.e., information indicating that an SMF change is required) before step, the AMFmay select a new SMF_Ndifferent from the SMF_Ein charge of a PDU session corresponding to the old PDU session ID. A PDU session creation procedure through the SMF_Nselected at stepmay be performed. The AMFmay transmit an SM context creation request message requesting SM context creation to the SMF_N.

The SM context creation request message may include at least one of S-NSSAI, DNN, or UE ID (slice identifier, data network name, or UE identifier, respectively).

2 620 500 500 620 620 1000 2 1000 620 1000 620 620 1000 620 b, a. At stepthe SMF_Nmay transmit a response message to the AMF. The AMFmay receive the response message from the SMF_N. The SMF_Nmay transmit a message requesting session related subscription information to the UDMbased on the UE ID received at stepThe UDMmay receive a message requesting session related subscription information from the SMF_N. The UDMmay transmit a response message to the message requesting session related subscription information to the SMF_N. The SMF_Nmay receive a response message to the message requesting session related subscription information from the UDM. The SMF_Nmay create an SM context based on the response message and create an SM context ID.

620 2 500 a The SMF_Nmay transmit a response message including the result (i.e., success or failure) of the request at stepand the SM context ID to the AMF.

3 620 720 720 620 620 500 2 620 620 710 720 710 a At step, the SMF_Nmay transmit an SM policy creation request message to the PCF_N. The PCF_Nmay receive the SM policy creation request message from the SMF_N. The SMF_Nmay perform selection on a PCF. For example, in the case that the SM context creation request message received from the AMFat stepincludes a PCF ID or information indicating to select the same PCF for the same S-NSSAI and DNN (or in the case that the SM context creation request message is stored as preconfigured information), the SMF_Nmay select a PCF based on the corresponding information. For example, the SMF_Nmay select the same PCF as the PCF_E(i.e., the PCF_Nand the PCF_Eare the same).

620 720 The SMF_Nmay transmit an SM policy creation request message for SM policy creation to the selected PCF (i.e., PCF_N).

4 720 1100 1100 720 720 3 1100 At step, the PCF_Nmay transmit a query request message (Nudr_DM_Query request) to the UDR. The UDRmay receive the query request message from the PCF_N. The PCF_Nmay transmit a query request message for requesting remaining allowed usage corresponding to an UE ID, DNN, and S-NSSAI included in the SM policy creation request message received at stepto the UDR.

5 1100 710 710 1100 1110 4 1100 At step, the UDRmay transmit an update notification message (Nudr_DM_Update Notify) to the PCF_E. The PCF_Emay receive the update notification message from the UDR. The UDRmay identify that the query request message received in stepis a message requesting remaining allowed usage for an UE ID, DNN, and S-NSSAI. In this case, the UDRmay identify whether there are PCFs in which SM policy association has not been terminated (i.e., PDU sessions in charge of PDU sessions that have not yet been terminated) among other PCFs that have requested or updated remaining allowed usage values for the UE ID, DNN, and S-NSSAI included in the received query request message.

1100 1100 1100 0 1100 710 710 1100 710 1100 3 FIG. The UDRmay identify whether there are PCFs in which SM policy association has not been terminated based on the message history previously transmitted and received to and from PCFs. The UDRmay identify whether there are PCFs in which SM policy association has not been terminated by requesting in advance information instructing to notify the UDRwhen SM policy association is terminated from the PCFs. That is, although not illustrated in, before step, the UDRmay transmit a subscription request message for instructing to notify itself when SM policy association for a PDU session to be monitored is terminated to the PCF_Ein the SM policy establishment procedure. The PCF_Emay receive the subscription request message from the UDR. Based on the subscription request message, the PCF_Emay transmit a message notifying the termination of policy association when policy association is terminated to the UDR.

1100 In the case that there are PCFs in which SM policy association has not been terminated (i.e., PDU sessions in charge of PDU sessions that have not yet been terminated) among other PCFs that have requested or updated the remaining allowed usage values for the UE ID, DNN, and S-NSSAI included in the received query request message, the UDRmay transmit an update notification message requesting a data usage update to the corresponding PCFs. The update notification message may include at least one of the UE ID, DNN, S-NSSAI, notification correlation information, data set identifier, or data usage update request indication (i.e., an indicator requesting a data usage update).

The notification correlation information may include identifier information for identifying communication between the UDR and the PCF. The data set identifier may include information indicating that it is data for remaining allowed usage within the PCF and the UDR.

3 FIG. 710 1100 610 710 610 710 1100 1100 1100 Although not illustrated in, each PCFthat has received an update notification message from the UDRmay identify PDU sessions based on information included in the update notification message, determine that it is a request for data usage update for the corresponding PDU sessions, and then request a data usage update to the SMF(s)for the corresponding PDU sessions. When each PCFreceives a response message to the data usage update request from the SMF(s), each PCFmay update remaining allowed usage based on aggregated usage included in the response message, and then transmit a response message to the update notification message transmitted by the UDRto the UDR. The response message to an update notification message transmitted by the UDRmay include at least one of remaining allowed usage, S-NSSAI, DNN, SUPI, notification correlation information, or data set identifier.

6 710 610 610 710 1100 5 710 5 1100 5 710 5 At step, the PCF_Emay transmit a request message to the SMF_E. The SMF_Emay receive the request message from the PCF_E. In the case that the update notification message received from the UDRat stepincludes a data usage update request indication, the PCF_Emay perform a data usage update for PDU sessions corresponding to S-NSSAI and DNN identified based on information included in the update notification message received at step. Even in the case that the update notification message received from the UDRat stepdoes not include a data usage update request indication and specific information (e.g., remaining allowed usage), the PCF_Emay perform a data usage update for PDU sessions corresponding to S-NSSAI and DNN identified based on information included in the update notification message received at step.

710 610 In order to perform an update, the PCF_Emay transmit a request message requesting a data usage update to the SMF_E.

7 610 710 710 610 610 710 At step, the SMF_Emay transmit a response message to the PCF_E. The PCF_Emay receive the response message from the SMF_E. In response to the request message requesting a data usage update, the SMF_Emay transmit a response message including aggregated data usage (i.e., data usage up to now) corresponding to S-NSSAI and DNN included in the request message to the PCF_E.

8 710 1100 1100 710 610 710 710 1100 At step, the PCF_Emay transmit a response message to the UDR. The UDRmay receive the response message from the PCF_E. In the case that aggregated data usage is included in the response message received from the SMF_E, the PCF_Emay update remaining allowed usage stored therein. The PCF_Emay transmit a response message including at least one of an UE ID, DNN, S-NSSAI, notification correlation information, data set identifier, aggregated data usage, or remaining allowed usage to the UDR.

9 1100 720 720 1100 8 1100 8 1100 4 1100 4 720 At step, the UDRmay transmit a response message to the PCF_N. The PCF_Nmay receive the response message from the UDR. If the response message received at stepincludes aggregated data usage and/or remaining allowed usage, the UDRmay update the remaining allowed usage values corresponding to S-NSSAI and DNN included in the response message received at stepbased on the corresponding information. If the UDRhas received a query message requesting remaining allowed usage at step, the UDRmay transmit a response message including the remaining allowed usage corresponding to the S-NSSAI, DNN, and UE ID received at stepto the PCF_N.

10 720 620 620 720 720 1100 9 720 620 620 3 At step, the PCF_Nmay transmit a response message to the SMF_N. The SMF_Nmay receive a response message from the PCF_N. In the case that the PCF_Nreceives a response message from the UDRat step, the PCF_Nmay transmit a response message to the SMF_Nin response to the SM policy creation request message received from the SMF_Nat step. The response message may include session related policy information and data monitoring related policy information.

11 100 500 610 620 710 720 1100 100 500 610 620 710 720 1100 At step, a PDU session establishment procedure may be performed in the UE, the AMF, the SMF_E, the SMF, the PCF_E, the PCF_N, and the UDR. For example, a rest of the PDU session establishment procedure may be performed in the UE, the AMF, the SMF_E, the SMF, the PCF_E, the PCF_N, and the UDR.

4 FIG. 500 10 is a message flow diagram illustrating an operation in which an AMFstores a PCF ID in an UE context in a PDU session creation procedure in a wireless communication systemaccording to the disclosure.

4 FIG. 2 3 FIGS.and 2 3 FIGS.and 600 610 620 700 710 720 With reference to, the SMFmay correspond to at least one of the SMF_Eor the SMF_Nof. The PCFmay correspond to at least one of the PCF_Eor the PCF_Nof.

1 100 500 200 500 100 200 At step, the UEmay transmit a PDU session establishment request message to the AMFthrough the RAN. The AMFmay receive the PDU session establishment request message from the UEthrough the RAN. The PDU session establishment message may include at least one of S-NSSAI, DNN, PDU session ID, or requested SSC mode.

The requested SSC mode may be a value representing one of an SSC mode 1, SSC mode 2, or SSC mode 3.

2 500 600 600 500 500 600 1 600 2 500 600 At step, the AMFmay transmit an SM context creation request message (Nsmf_PDUSession_CreateSMContext request) to the SMF. The SMFmay receive the SM context creation request message from the AMF. For example, the AMFmay select the SMFto be in charge of a PDU session based on S-NSSAI and DNN included in the PDU session establishment request message received at step. A PDU session creation procedure through the SMFselected at stepmay be performed. The AMFmay transmit an SM context creation request message requesting SM context creation to the SMF.

The SM context creation request message may include the following information:

S-NSSAI, DNN, and UE ID: They may be a slice identifier, data network name, and UE identifier, respectively.

1 Requested SSC mode: When a requested SSC mode is received at step, the corresponding information may be included.

3 600 1000 600 1000 2 At step, the SMFmay perform a subscription retrieval operation with the UDM. For example, the SMFmay receive subscriber information related to the session from the UDMbased on the UE ID included in the SM context creation request message received at step. The subscriber information may include a subscribed SSC mode for the UE ID.

4 600 500 500 600 600 1000 3 2 600 2 At step, the SMFmay transmit a SM context creation response message (Nsmf_PDUSession_CreateSMContext response) to the AMF. The AMFmay receive the SM context creation response message from the SMF. The SMFmay create an SM context and an SM context ID based on the information received from the UDMat step. The SM context may include an allowed SSC mode based on the subscribed SSC mode and the requested SSC mode. In response to step, the SMFtransmits an SM context creation response message including the SM context ID and the result (i.e., success or failure) of the request at step.

5 600 1000 700 600 700 700 700 600 700 700 600 At step, the SMFmay perform an SM policy association procedure together with the UDMand the PCF. The SMFmay select the PCFfor an SM policy creation request and transmit an SM policy creation request message to the selected PCF. The PCFmay receive the SM policy creation request message from the SMF. The PCFmay create a policy for the session (i.e., SM policy) based on the SM policy creation request message. The PCFmay transmit a response message including policy information on the session to the SMF.

700 600 600 700 In the case that the corresponding PDU session (or S-NSSAI and DNN) in which establishment is requested is a monitoring target, the PCFmay transmit a response message including policy information for data usage monitoring (e.g., traffic to be monitored, monitoring report cycle) to the SMF. The SMFmay receive the response message from the PCF.

6 600 4 600 4 300 At step, the SMFmay perform an Nsession establishment operation. For example, the SMFmay create an Nsession with the UPFbased on the S-NSSAI and DNN.

7 600 1 2 1 2 500 500 1 2 600 600 1 2 1 2 500 At step, the SMFmay transmit an NNmessage transfer request message (Namf_Communication_NNMessageTransfer request) to the AMF. The AMFmay receive the NNmessage transfer request message from the SMF. The SMFmay transmit an NNmessage transfer request message including information (i.e., Ninformation) to be transferred to the UE for the session and information (Ninformation) to be transferred to the base station to the AMF.

1 2 700 5 600 1 2 600 5 600 600 1 2 The NNmessage may include a PCF ID of the PCFselected at step. In this case, in the case that the corresponding PDU session in which establishment is requested is a PDU session to be monitored, the SMFmay include a PCF ID in the NNmessage. For example, in the case that the SMFreceives policy information for monitoring at step, the SMFmay identify whether the corresponding PDU session in which establishment is requested is a PDU session to be monitored based on the policy information. Alternatively, in the case that the corresponding PDU session in which establishment is requested is a PDU session to be monitored and is a PDU session corresponding to an SSC mode 3, the SMFmay include a PCF ID in the NNmessage.

8 500 600 600 500 1 2 7 500 100 At step, the AMFmay transmit a response message to the SMF. The SMFmay receive the response message from the AMF. When a PCF ID is included in NNmessage transfer request message received at step, the AMFmay store the PCF ID as information on S-NSSAI, DNN, and PDU session ID in UE context information on the UE(i.e., UE ID).

500 600 1 2 600 7 The AMFmay transmit a response message to the SMFin response to the NNmessage transfer request message received from the SMFat step.

9 100 500 600 700 1000 100 500 600 700 1000 At step, a PDU session establishment procedure may be performed between the UE, the AMF, the SMF, the PCF, and the UDM. For example, a rest of the PDU session establishment procedure may be performed in the UE, the AMF, the SMF, the PCF, and the UDM.

5 FIG. 700 500 600 10 is a message flow diagram illustrating a method of selecting the same PCFfor S-NSSAI/DNN based on information received from the AMFby the SMFin a PDU session creation procedure in a wireless communication systemaccording to the disclosure.

5 FIG. 2 3 FIGS.and 2 3 FIGS.and 600 610 620 700 710 720 With reference to, the SMFmay correspond to at least one of the SMF_Eor the SMF_Nof. The PCFmay correspond to at least one of the PCF_Eor the PCF_Nof.

1 100 500 200 500 100 200 At step, the UEmay transmit a PDU session establishment request message to the AMFthrough the RAN. The AMFmay receive the PDU session establishment request message from the UEthrough the RAN. The PDU session establishment request message may include at least one of S-NSSAI, DNN, or PDU session ID.

300 610 In the case of an SSC mode 3 procedure (i.e., a procedure for creating a new PDU session to replace an old PDU session because a change of the anchor UPFis required for an old PDU session managed by the SMF_E), an old PDU session ID may be included. The old PDU session ID indicates identifier information on the existing PDU session established with the same S-NSSAI and DNN as those included in the PDU session establishment request message.

2 500 600 600 500 500 600 1 500 1 1 500 600 610 a, At stepthe AMFmay transmit an SM context creation request message to the SMF. The SMFmay receive the SM context creation request message from the AMF. The AMFmay select an SMFto be in charge of a new PDU session corresponding to the S-NSSAI and DNN included in the PDU session establishment request message received at step. When the AMFhas received an old PDU session ID at stepand received an SMF relocation indication (i.e., information indicating that an SMF change is required) before step, the AMFmay select a new SMFdifferent from the SMF_Ein charge of the PDU session corresponding to the old PDU session ID.

500 1 1 500 700 600 700 In the case that the AMFhas received an SMF relocation indication (i.e., information indicating that an SMF change is required) before step, and that there is the existing PDU session corresponding to S-NSSAI and DNN received at stepin the UE context information, the AMFmay transmit an SM context creation request message including a PCF ID corresponding to the PCFto the SMFso that the same PCFas the PCF in charge of the existing PDU session may be selected when selecting a PCF for a new PDU session.

500 In the case that the PCF ID is stored in information for each session within the UE context, the AMFmay utilize the information.

500 1600 600 If a PCF ID for a PDU session in the UE context is not stored, the AMFmay receive a PCF ID through the NRFor receive a PCF ID through the SMFfor the corresponding PDU session.

1600 600 500 1600 600 In the case of receiving a PCF ID through the NRFor the SMF, a request message transmitted from the AMFto the NRFand the SMFmay include a PDU session ID, SM context ID or UE ID, S-NSSAI, and DNN.

1600 600 600 600 The NRFor the SMFmay identify a PCF ID based on information included in a message received from the SMFand transmit a response message including the identified PCF ID to the SMF.

500 600 The AMFmay transmit an SM context request message requesting SM context creation to the selected SMF. The SM context message may include at least one of the following information:

S-NSSAI, DNN, and UE ID: They may include a slice identifier, data network name, and UE identifier, respectively.

PCF ID: The SM context message may include a PCF ID for the existing PDU session for S-NSSAI and DNN.

2 600 500 500 600 600 1000 2 600 1000 b, a. At stepthe SMFmay transmit a response message to the AMF. The AMFmay receive the response message from the SMF. The SMFmay request and receive session related subscription information to and from the UDMbased on the UE ID received at stepThe SMFmay create an SM context and an SM context ID based on the session related subscription information received from the UDM.

600 2 500 a The SMFmay transmit a response message including the result (i.e., success or failure) of the request at stepand an SM context ID to the AMF.

3 600 700 700 600 600 700 500 2 600 700 600 a At step, the SMFmay transmit a policy creation request message (Npcf_SMPolicyCreate Request) to the PCF. The PCFmay receive the policy creation request message from the SMF. The SMFmay perform an operation for selecting the PCF. In the case that the SM context creation request message received from the AMFat stepincludes a PCF ID or information indicating to select the same PCF for the same S-NSSAI and DNN (or in the case that the SM context creation request message is stored as preconfigured information), the SMFmay select the PCFbased on the information (i.e., in the case that the PCF ID is included, the SMFmay select the PCF corresponding to the PCF ID).

2 600 700 a In the case that the SM context creation request message received at stepincludes a PCF ID, the SMFmay transmit an SM policy creation request message including PDU session exist (i.e., information indicating that the existing PDU session exists) to the PCF.

500 600 2 a In the case that the SM context creation request message transmitted from the AMFto the SMFat stepincludes an SM policy association ID, the PDU session exist may include the SM policy association ID.

600 700 For example, the SMFmay transmit a policy creation request message including at least one of an UE ID, DNN, S-NSSAI, or PDU session exist to the PCF.

4 700 1100 1100 700 3 700 3 At step, the PCFmay transmit a query request message (Nudr_DM_Query request) to the UDR. The UDRmay receive the query request message from the PCF. In the case that the policy creation request message received at stepincludes PDU session exist, but does not include an SM policy association ID, the PCFmay identify the existing PDU sessions corresponding to DNN and S-NSSAI included in the policy creation request message received at stepand transmit a message requesting to perform a data usage update to SMFs in charge of the identified PDU sessions.

3 700 In the case that the policy creation request message received at stepincludes PDU session exist and SM policy association ID(s), the PCFmay identify the existing PDU session(s) corresponding to the SM policy association ID(s) and transmit a message requesting to perform a data usage update to the SMF(s) in charge of the identified PDU session(s).

3 700 3 Even if the policy creation request message received at stepdoes not include PDU session exist, the PCFmay identify existing PDU sessions corresponding to the DNN and S-NSSAI included in the policy creation message received at stepand transmit a message requesting to perform a data usage update to SMFs in charge of the identified PDU sessions.

700 700 3 1100 The PCFdetermines that a data usage update is required, and when the corresponding update is completed, the PCFmay transmit a query request message for receiving remaining allowed usage corresponding to the UE ID, DNN, and S-NSSAI included in the SM policy creation request message received at stepto the UDR.

5 1100 700 700 1100 1100 4 1100 700 At step, the UDRmay transmit a response message to the PCF. The PCFmay receive a response message from the UDR. The UDRmay identify that the query request message received at stepis a message requesting remaining allowed usage for an UE ID, DNN, and S-NSSAI. The UDRmay transmit a response message including a remaining allowed usage value to the PCF.

The disclosure relates to a 5G or 6G communication system for supporting higher data rates.

6 FIG. 100 10 is a block diagram illustrating a UEin a wireless communication systemaccording to the disclosure.

6 FIG. 100 101 102 103 103 101 102 100 100 100 100 103 101 102 As illustrated in, the UEof the disclosure may include a transceiver, a memory, and a processor. The processor, the transceiver, and the memoryof the UEmay operate according to the communication method of the UEdescribed above. However, the components of the UEare not limited to the above-described examples. For example, the UEmay include more or fewer components than the above-described components. Further, the processor, the transceiver, and the memorymay be implemented in the form of a single chip.

101 100 100 200 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 200 101 101 101 The transceiveris a general term for a receiver of the UEand a transmitter of the UE, and may transmit and receive signals to and from the base stationor network entities,,,,,,,,,,,, and. The signals transmitted and received to and from the base stationmay include control information and data. To this end, the transceivermay be composed of an RF transmitter that up-converts and amplifies a frequency of a signal to be transmitted, and an RF receiver that low-noise amplifies a received signal and that down-converts a frequency thereof. However, this is only an embodiment of the transceiver, and the components of the transceiverare not limited to the RF transmitter and the RF receiver.

101 Further, the transceivermay include a wired or wireless transceiver and include various components for transmitting and receiving signals.

101 103 103 Further, the transceivermay receive a signal through a wireless channel and output the signal to the processor, and transmit a signal output from the processorthrough the wireless channel.

101 Further, the transceivermay receive a communication signal and output it to the processor, and transmit the signal output from the processor to the network entity through a wired or wireless network.

102 100 102 102 The memorymay store programs and data required for the operation of the UE. Further, the memorymay store control information or data included in a signal acquired from the UE. The memorymay include storage media such as a read only memory (ROM), a random access memory (RAM), a hard disk, a compact disc read-only memory (CD-ROM), and a digital versatile disc (DVD), or a combination of storage media.

103 100 103 103 The processormay control a series of processes so that the UEmay operate according to the foregoing embodiment of the disclosure. The processormay include at least one processor. For example, the processormay include a communication processor (CP) that performs the control for communication and an application processor (AP) that controls upper layers such as application programs.

7 FIG. 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 10 is a block diagram illustrating network entities,,,,,,,,,,,, andin a wireless communication systemaccording to the disclosure.

7 FIG. 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 201 202 203 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 203 201 202 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 203 201 202 As illustrated in, the network entities,,,,,,,,,,,, andof the disclosure may include a transceiver, a memory, and a processor. According to a communication method of the network entities,,,,,,,,,,,, anddescribed above, the processor, the transceiver, and the memoryof the network entities,,,,,,,,,,,, andmay operate. However, components of the network entities,,,,,,,,,,,, andare not limited to the above-described examples. For example, the network entities,,,,,,,,,,,, andmay include more or fewer components than the above-described components. Further, the processor, the transceiver, and the memorymay be implemented in the form of a single chip.

201 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 100 201 201 201 201 The transceiveris a general term for a receiver of the network entities,,,,,,,,,,,, andand a transmitter of the network entities,,,,,,,,,,,, andand may transmit and receive signals to and from the UEor another network entity. In this case, the transmitted and received signals may include control information and data. To this end, the transceivermay be composed of an RF transmitter that up-converts and amplifies a frequency of a signal to be transmitted, and an RF receiver that low-noise amplifies a received signal and that down-converts a frequency thereof. However, this is only an embodiment of the transceiver, and the components of the transceiverare not limited to the RF transmitter and the RF receiver. The transceivermay include a wired or wireless transceiver, and include various components for transmitting and receiving signals.

201 203 203 Further, the transceivermay receive a signal through a communication channel (e.g., wireless channel) and output the signal to the processor, and transmit a signal output from the processorthrough the communication channel.

201 100 Further, the transceivermay receive a communication signal and output it to the processor, and transmit the signal output from the processor to the UEor another network entity through a wired or wireless network.

202 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 202 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 202 The memorymay store programs and data required for the operation of the network entities,,,,,,,,,,,, and. Further, the memorymay store control information or data included in a signal acquired from the network entities,,,,,,,,,,,, and. The memorymay be composed of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD or a combination of storage media.

203 300 400 500 600 700 800 900 1000 1100 1500 1600 1700 1800 203 The processormay control a series of processes so that the network entities,,,,,,,,,,,, andmay operate according to the foregoing embodiments of the disclosure. The processormay include at least one processor. Methods according to the embodiments described in the claims or specification of the disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

The disclosure may be used in the electronics industry and the information and communication industry.